Sexing a kitten can prove somewhat challenging due to the fur covering their genitals. To put it simply, you may not have an easy time determining their sex with just a quick glance under their tail.
But it’s important to know your kitten’s sex, says Dr Nick Horniman, a veterinary surgeon and founder of online pet pharmacy MyPetsVet. Sexing your kitten at an early age can help you make the most informed decisions for their health, nutrition, and behaviour, he explains.
“For example, neutering or spaying a cat can have different health benefits and risks depending on their sex,” Dr Horniman continues, adding that sexing is also important for identifying potential health issues related to reproductive organs. You may also want to know a kitten’s sex for breeding purposes.
Below, get all the details on sexing kittens—including why it’s important to wait until they’re a few weeks old.
Why Is Sexing Kittens Difficult?
Without knowing what to look for, sexing a kitten can be tricky. Age and development stages pose the biggest obstacles. For starters, in the early days, male kitten genitalia isn’t obvious in the way you might expect (more on this below).
“The genitalia on a male kitten are very indistinct until they are several months old,” explains Dr TB Thompson, a veterinarian in Arizona, USA.
In addition, some male kittens may have underdeveloped testes that aren’t immediately visible, Dr Horniman says. As a result, the genitalia of female and male kittens may appear very similar.
That said, some characteristics can help you set them apart.
How To Work Out A Kitten’s Sex From Their Genitals
You can determine a kitten’s sex in a few different ways, but the most obvious one involves looking at their genitals. That said, keep in mind you may not get a clear answer if you check in their first few weeks of life.
Handling a kitten during sexing
Handling kittens requires care, meaning it’s essential to go gently!
“When trying to determine the sex of a kitten, I hold them around their thorax (chest area) and lift their tail,” explains Dr Thompson. “Otherwise, I hold them feet-down but support their weight in my hand rather than having them stand.”
If the kitten is very young—think two weeks old or less— “I may hold them with their feet up,” she says.
Got a bit of a wriggler on your hands? Having someone pet the kitten on the head to distract them while you check can help, Dr Thompson suggests.
What Male Kitten Genitals Look Like
Sexing male kittens can be tricky as their genitalia change in appearance over time. In the first weeks of their lives, the most noticeable aspect is a round opening in the fur and skin below their anus, Dr Thompson says.
You won’t see their penis during these early months, as it’s entirely covered by a skin sheath called the prepuce. The testicles remain in the abdomen until the kitten reaches two to four months of age, Dr Thompson says. But after this time, things start changing. Their testicles begin to become visible in the scrotum and the penis grows slightly in size, though it remains hidden.
It’s not until puberty, which occurs between four to 12 months of age, that the genitals become more noticeable. After puberty, the cat’s penis will reach ½-1 inch in length, though it still generally won’t be visible unless a vet sedates the kitten and retracts the prepuce,” Dr Thompson says.
What Female Kitten Genitals Look Like
Determining female kitten genitalia isn’t much more straightforward.
“A female kitten’s genitals are not apparent, except as a small opening in the fur,” Dr Thompson says. Still, they’re a bit different from male kitten genitalia.
For one, the female opening has a slightly more linear shape and may appear as a line of skin—with no hair—directly adjacent to the anus, according to Dr Thompson.
In female kittens, this small opening is also much closer to the anus, though the specific length of the space can vary depending on the breed, age, and size of the kitten, Dr Horniman says.
Even after puberty and entering heat, a female cat’s genitalia doesn’t change in appearance.
Other Ways To Work Out A Kitten’s Sex
Ultimately, directly examining a kitten’s genitalia remains the most accurate way to determine their sex, according to Dr Horniman. But if this doesn’t offer a conclusive answer, a few other key traits might offer some clues—though some are more reliable than others!
Fur colour
You can sometimes use your kitten’s fur colour to figure out their sex.
“Calico and tortoiseshell cats are typically female, while orange tabbies are more often male,” Dr Horniman explains. He emphasises, however, that this isn’t a guarantee. In short, you don’t want to use it as the only method of determining sex.
Behaviour
As cats get older, you might notice some slightly different behaviours in male and female cats. For instance, male felines are more likely to engage in spraying, or territory marking, but they’re often more sociable and playful. Meanwhile, female cats may be more likely to use the litter box, but they may show signs of fear and aggression.
However, Dr Thompson says kittens don’t reliably display any obvious differences in behaviour characteristics. These traits usually don’t show up until cats reach sexual maturity, around six to 12 months of age. By this time, genitalia differences are clearer, so you might already know their sex!
Faces
Facial features can also sometimes offer clues to your cat’s sex. According to Dr Horniman, male cats often have a broader, more angular head and a more prominent jawline, for example.
But like fur colour, this method isn’t 100% reliable. Even cats of the same sex can have significant variations in their facial features, Dr Horniman says.
Body shape and size
The size and shape of a kitten’s body could also point toward one sex over the other. According to Dr Horniman, male kittens are typically larger and more muscular than female kittens, especially in the shoulders and neck area. Female kittens tend to have a more streamlined body shape and a smaller size.
But again, these differences may not be readily apparent in young kittens, and body size and shape can vary widely among individual cats, he says.
Can you get an ultrasound?
“I am not aware of any test done in general clinical practice that can determine a kitten’s sex before it’s born,” Dr Thompson says.
That said, tests done in research settings have successfully determined a kitten’s sex before birth. For example, in one study scientists took DNA samples from cat embryos to determine the sex of the kittens.
Yet while it might go without saying, vets don’t offer this type testing. For now, it remains limited to research only.
At What Age Can You Work Out A Kitten’s Sex?
If you’ve become a pet parent to some new arrivals, you may feel tempted to immediately check their sex. But you may want to hold off, at least for a few weeks.
“It’s generally recommended to wait until a kitten is at least six to eight weeks old before attempting to determine their sex,” Dr Horniman says. By this point, the genitals are more distinguished and often easier to determine.
But that’s not the only reason to delay. In many mother-offspring relationships, the early days are highly important—and this goes for cats, too.
“Handling very young kittens too much can be stressful for both the kitten and the mother and may disrupt their relationship,” he adds. “It’s important to give the mother and her litter plenty of time to bond and develop their relationship without interference.”
Young kittens won’t miss out on anything important, even if you don’t know their sex until they reach eight weeks of age. “There are no differences in care required for healthy male and female kittens,” Dr Thompson says.
Once they reach eight weeks, you should be able to check their sex for prospective pet parents waiting to take them home.
